Salinity stress accelerates the effect of cadmium toxicity on soil N dynamics and cycling: Does joint effect of these stresses matter?
| Autor: | S H Kiani, Fayez Raiesi, Mahshid Razmkhah |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Salinity
Nitrogen Health Toxicology and Mutagenesis chemistry.chemical_element 010501 environmental sciences complex mixtures 01 natural sciences Soil Soil Pollutants Organic matter Biomass Nitrogen cycle Soil Microbiology 0105 earth and related environmental sciences chemistry.chemical_classification Cadmium Chemistry Public Health Environmental and Occupational Health 04 agricultural and veterinary sciences General Medicine Mineralization (soil science) Nitrogen Cycle Urease Pollution Environmental chemistry Loam Soil water 040103 agronomy & agriculture 0401 agriculture forestry and fisheries Nitrification Medicago sativa |
| Zdroj: | Ecotoxicology and Environmental Safety. 153:160-167 |
| ISSN: | 0147-6513 |
| Popis: | The objective of this study was to determine responses of soil nitrogen (N) transformation, microbial biomass N, and urease activity to the combined effect of cadmium (Cd) toxicity (0 and 30 mg kg−1) and NaCl stress (0, 7.5 and 15 dS m−1) in a clay loam soil unamended (0%) or amended with alfalfa residues (1%, w/w). Cd, NaCl, and alfalfa residues were added to the soil, and the mixtures were incubated for 90 days under standard laboratory conditions (25 ± 1 °C and 70% of water holding capacity [WHC]). The results showed that salinity increased soil Cd availability and toxicity and subsequently decreased soil microbial N transformations (i.e., potential ammonification and nitrification as well as net N mineralization), arginine ammonification and nitrification rates, microbial biomass N, and urease activity. The adverse effects of salinity on soil microbial properties were greater in Cd-polluted than unpolluted soils, at high than low salinity levels, but were lower in residue-amended than unamended soils. These effects were mainly attributed to the increased Cd availability under saline conditions or the decreased Cd availability with residue addition. All the measured soil microbial attributes showed a negative correlation with the available Cd content in the soil. The interaction or combined effects of Cd and NaCl on soil microbial attributes were mostly synergistic in residue-unamended soils but antagonistic in residue-amended soils. The addition of organic residues to Cd-polluted soils may moderate salinity effect, and thus could stimulate the activity of ammonifiers and nitrifiers, as well as urease. |
| Databáze: | OpenAIRE |
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